United States Environmental Protection Agency 1200 Pennsylvania Avenue, N.W. Washington, D.C. 20460 September 2011
Office of Solid Waste and Emergency Response


# Support Document for the Revised National Priorities List Final Rule – Armstrong World IndustriesArmstrong World Industries NPL Listing Support Document September 2011



# Support Document for the Revised National Priorities List Final Rule Armstrong World Industries September 2011

Site Assessment and Reme dy Decisions Branch Office of Superfund Remediati on and Technology Innovation Office of Solid Waste and Emergency Response U.S. Environmental Protection Agency Washington, DC 20460Armstrong World Industries NPL Listing Support Document September 2011



### Table of Contents

Executive Summary .................................................................................................................................... ii

Introduction ............................................................................................................................................... iii

Background of the NPL .......................................................................................................................... iii

Development of the NPL ........................................................................................................................ iii

Hazard Ranking System .......................................................................................................................... iv

Other Mechanisms for Listing ................................................................................................................. v

Organization of this Document ................................................................................................................ v

Glossary

............................................................................................................................... ................... vi

1. List of Commenters and Correspondence ....................................................................................... 1

2. Site Description .................................................................................................................................. 1

3. Summary of Comments ..................................................................................................................... 1

3.1 Support for listing ......................................................................................................................... 2

3.2 Site Name ..................................................................................................................................... 2

3.3 Liability ........................................................................................................................................ 3

3.4 Hazardous Substances Associated With Sources ......................................................................... 3

3.5 Source Hazardous Waste Quantity ............................................................................................... 4

3.6 Probable Points of Entry from Sources ........................................................................................ 9

3.7 Attribution

............................................................................................................................... ... 10

4. Conclusion

............................................................................................................................... ......... 13

iArmstrong World Industries NPL Listing Support Document September 2011



## Executive Summary

Section 105(a)(8)(B) of CERCLA, as amended by SARA, requires that the EPA prepare a list of national priorities among the known releases or threatened releases of hazardous substances, pollutants, or contaminants throughout the United States. An original National Prio rities List (NPL) was promulgated on September 8, 1983 (48 FR 40658). CERCLA requires that EPA update the list at least annually.

This document provides responses to public comments r eceived on the Armstrong World Industries site, proposed on October 21, 2010 (75 FR 64976). This site is being added to the NPL based on an evaluation under EPA’s Hazard Ranking System (HRS) in a final rule published in the Federal Register in September 2011.

iiArmstrong World Industries NPL Listing Support Document September 2011



## Introduction

This document explains the rationale for adding the Arms trong World Industries site in Macon, Georgia, to the National Priorities List (NPL) of uncontrolled hazardous waste sites and provides responses to public comments received on this site listing proposal. The EPA proposed this site to the NPL on Octobe r 21, 2010 (75 FR 64976). This site is being added to the NPL based on an evalua tion under the Hazard Ranking System (HRS) in a final rule published in the Federal Register in September 2011.


### Background of the NPL

In 1980, Congress enacted the Comprehensive Enviro nmental Response, Compensation, and Liability Act (CERCLA), 42 U.S.C. Sections 9601 et seq . in response to the dangers of uncontrolled hazardous waste sites. CERCLA was amended on October 17, 1986, by the Supe rfund Amendments and Reauthorization Act (SARA), Public Law No. 99-499, stat., 1613 et seq. To implement CERCLA, EPA promulgated the revised National Oil and Hazardous Substances Pollution Con tingency Plan (NCP), 40 CFR Part 300, on July 16, 1982 (47 FR 31180), pursuant to CERCLA Section 105 and Executive Order 12316 (46 FR 42237, August 20, 1981). The NCP, further revised by EPA on September 16, 1985 (50 FR 37624) and November 20, 1985 (50 FR 47912), sets forth guidelines and procedures needed to respond under CERCL A to releases and threaten ed releases of hazardous substances, pollutants, or contaminants. On March 8, 1990 (55 FR 8666), EPA further revised the NCP in response to SARA.

Section 105(a)(8)(A) of CERCLA, as amended by SARA, requires that the NCP include

criteria for determining priorities among releases or threatened releases throughout the United States for the purpose of taking remedial action and, to the extent practicable, take into account the potential urgency of such action, for the purpose of taking removal action.

Removal action involves cleanup or other actions that ar e taken in response to emergency conditions or on a short-term or temporary basis (CERCLA Section 101). Remedial action is generally long-term in nature and involves response actions that are consistent with a permanent remedy for a release (CERCLA Section 101). Criteria for placing sites on the NPL, which makes them elig ible for remedial actions financed by the Trust Fund established under CERCLA, were included in the HRS. EPA promulgated the HRS as Appendix A of the NCP (47 FR 31219, July 16, 1982). On December 14, 1990 (56 FR 51532), EPA promulgated revisions to the HRS in response to SARA, and established the effective date for the HRS revisions as March 15, 1991.

Section 105(a)(8)(B) of CERCLA, as amended, requires that the statutory criteria provided by the HRS be used to prepare a list of national priorities among the known rel eases or threatened releases of hazardous substances, pollutants, or contaminants throughout the United States. The list, which is Appendix B of the NCP, is the NPL.

An original NPL of 406 sites was promulgated on September 8, 1983 (48 FR 40658). At that time, an HRS score of 28.5 was established as the cutoff for listing because it yielded an initial NPL of at least 400 sites, as suggested by CERCLA. The NPL has been expanded several times si nce then, most recently on March 10, 2011 (76 FR 13089). The Agency also has published a number of proposed rulemakings to add sites to the NPL. The most recent proposal was on March 10, 2011 (76 FR 13113).


### Development of the NPL

The primary purpose of the NPL is stated in the legi slative history of CERCLA (Report of the Committee on Environment and Public Works, Senate Repor t No. 96-848, 96th Cong., 2d Sess. 60 [1980]).

iiiArmstrong World Industries NPL Listing Support Document September 2011

The priority list serves primarily informational purposes, identifying for the States and the public those facilities and sites or other releases which appear to warrant remedial actions. Inclusion of a facility or site on the list does not in itself re flect a judgment of the activities of its owner or operator, it does not require those persons to un dertake any action, nor does it assign liability to any person. Subsequent governme nt actions will be necessary in order to do so, and these actions will be attended by all appropr iate procedural safeguards.

The NPL, therefore, is primarily an informational and ma nagement tool. The identification of a site for the NPL is intended primarily to guide EPA in determining which sites warrant further investigation to assess the nature and extent of the human health and environmental risks associated with the site and to determine what CERCLAfinanced remedial action(s), if any, may be appropriate. The NPL also serves to notify the public of sites EPA believes warrant further investigation. Finally, listing a s ite may, to the extent potentially responsible parties are identifiable at the time of listing, serve as notice to su ch parties that the Agency may initiate CERCLA-financed remedial action.

CERCLA Section 105(a)(8)(B) directs EPA to list priority sites among the known releas es or threatened release of hazardous substances, pollutants, or contaminants, a nd Section 105(a)(8)(A) directs EPA to consider certain enumerated and other appropriate factors in doing so. Thus, as a matter of policy, EPA has the discretion not to use CERCLA to respond to certain types of releases. Wh ere other authorities exist, placing sites on the NPL for possible remedial action under CERCLA may not be appropria te. Therefore, EPA has chosen not to place certain types of sites on the NPL even though CERCLA does not exclude such action. If, however, the Agency later determines that sites not listed as a matter of policy are not being properly responded to, the Agency may consider placing them on the NPL.


### Hazard Ranking System

The HRS is the principle mechanism EPA uses to place uncontrolled waste sites on the NPL. It is a numerically based screening system that uses information from initial, limited investigations -- the preliminary assessment and site inspection -- to assess the relative potential of sites to po se a threat to human health or the environment. HRS scores, however, do not determine the sequence in wh ich EPA funds remedial response actions, because the information collected to develop HRS scores is not sufficient in itself to determine either the extent of contamination or the appropriate response for a particular site. Moreover, the sites with the highest scores do not necessarily come to the Agency's atten tion first, so that addressing sites strictly on the basis of ranking would in some cases require stopping work at sites where it was already underway. Thus, EPA relies on further, more detailed studies in the remedial investigation/f easibility study that typically follows listing.

The HRS uses a structured value analysis approach to scoring sites. This approach assigns numerical values to factors that relate to or indicate risk, based on conditions at the site. The factors are grouped into three categories. Each category has a maximum value. The categories are:

• likelihood that a site has released or has the potential to release hazardous substances into the environment;

• characteristics of the waste (toxicity and waste quantity); and

• people or sensitive environments (targets) affected by the release.

Under the HRS, four pathways can be scored for one or more threats as identified below:

• Ground Water Migration (S gw ) - drinking water

ivArmstrong World Industries NPL Listing Support Document September 2011

• Surface Water Migration (S sw ) The following threats are evaluated for two separate migration components, overland/flood migration and ground water to surface water. - drinking water - human food chain - sensitive environments

• Soil Exposure (S s ) - resident population - nearby population - sensitive environments

• Air Migration (S a ) - population - sensitive environments

After scores are calculated for one or more pathways acco rding to prescribed guidelines, they are combined using the following root-mean-square equation to determine the overall site score (S), which ranges from 0 to 100 :



### 4 S + S + S + S = S 2

a 2

s 2

sw 2
gw

If all pathway scores are low, the HRS score is low. Howe ver, the HRS score can be relatively high even if only one pathway score is high. This is an important re quirement for HRS scoring because some extremely dangerous sites pose threats through only one pathway. For exam ple, buried leaking drums of hazardous substances can contaminate drinking water wells, but -- if the drums ar e buried deep enough and the substances not very volatile -- not surface water or air.


### Other Mechanisms for Listing

There are two mechanisms other than the HRS by which sites can be placed on the NPL. The first of these mechanisms, authorized by the NCP at 40 CFR 300.425(c)(2 ), allows each State and Territory to designate one site as its highest priority regardless of score. Th e last mechanism, authorized by the NCP at 40 CFR 300.425(c)(3), allows listing a site if it meets the following three requirements:

• Agency for Toxic Substances and Disease Registry (ATSDR) of the U.S. Public Health Service has issued a health advisory that recommends di ssociation of individuals from the release;

• EPA determines the site poses a significant threat to public health; and

• EPA anticipates it will be more cost-effective to use its remedial authority than to use its emergency removal authority to respond to the site.


### Organization of this Document

The following section contains EPA responses to site-s pecific public comments received on the proposal of the Armstrong World Industries site on October 21, 2010 (75 FR 64976). The site discussion begins with a list of commenters, followed by a site description, a summary of comments, and Agency responses to each comment. A concluding statement indicates the effect of the comments on the HRS score for the site.

vArmstrong World Industries NPL Listing Support Document September 2011

vi 

### Glossary

The following acronyms and abbreviations are used throughout the text:

Agency U.S. Environmental Protection Agency

AIP Allied Industrial Park

AWI Armstrong World Industries

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act of 1980, 42 U.S.C. Sections 9601 et seq ., also known as Superfund

CFR Code of Federal Regulations

EPA U.S. Environmental Protection Agency

ESI Expanded Site Investigation

FR Federal Register

FMNOL Former Macon Naval Ordinance Landfill

FMNOP Former Macon Naval Ordinance Plant

HRS Hazard Ranking System, Appendix A of the NCP

HRS score Overall site score calculated using the Hazard Ranking System; ranges from 0 to 100

MDL Method detection limit

NCP National Oil and Hazardous Substances Pollutio n Contingency Plan, 40 C.F.R. Part 300

NPL National Priorities List, Appendix B of the NCP

PAH Polycyclic aromatic hydrocarbon

PCB Polychlorinated biphenyl

PPE Probable point of entry

PRP Potentially responsible party

RCRA Resource Conservation and Recovery Act

RI/FS Remedial investigation and feasibility study

SARA Superfund Amendments and Reauthorization Act

SI Site Inspection

START Superfund Technical Assistance and Response Team

SVOC Semi-volatile organic compound

TDL Target Distance Limit

VOC Volatile organic compound

WWTP Wastewater Treatment PlantArmstrong World Industries NPL Listing Support Document September 2011



## 1. List of Commenters and Correspondence

EPA-HQ-SFUND-0640-0006 Comment Submitted by Steven Pfeiffenberger, Vice President, Environment, Health, and Safety, Armstrong World Industries, Inc. (AWI)

EPA-HQ-SFUND-0640-0005 Comment Submitted by Bonnie Allyn, Barnett, Drinker Biddle & Reath LLP on behalf of Steven Pfeiffenberger, Vice Presidnet, Environment, Health & Safety, Armstrong World Industries, Inc. (AWI)

EPA-HQ-SFUND-0640-0004 Letter to A. Stanley Meibur g, Acting Regional Administrator, Region 4, USEPA, from F. Allen Barnes, Director, Georgia Department of Natural Resources


## 2. Site Description

The Armstrong World Industries site (AWI site) consists of three sources and associated releases of hazardous substances to the surface water migration pathway. All three sources are documented to contain hazardous substances from deposited waste as a result of operati ons at the AWI facility. Specifically, polychlorinated biphenyls (PCBs) have been associated with operations at the AWI facility, such as the processing of newspaper print (inks). Source 1, a wastewater treatment plant (WWTP) landfill located on the AWI facility, was documented as containing hazardous substances including PCBs. Overland flow from Source 1 migrates into a drainage ditch which conveys surface water toward we tlands and Rocky Creek, a human food chain fishery. Source 2, the combined AWI remote landfill and Form er Macon Naval Ordnance Landfill (FMNOL), contains hazardous substances resulting from activities at the AWI facility and the Former Macon Naval Ordnance Plant (FMNOP). Source 3, contaminated soil surrounding the AWI remote landfill, is documented as containing hazardous substances including semi-volatile organic compounds (SVOCs), metals and PCBs. Overland flow from these sources migrates into wetlands and Rocky Cr eek. Portions of Source 3 were documented as located directly within wetlands, establishing an observed release by direct observation.

An observed release by chemical analysis has been es tablished as release samples within Rocky Creek, located downgradient of site sources, contai ned hazardous substances (including PCBs that have been associated with AWI facility operations) significantly great er than background levels and the increase is due at least in part to releases from the AWI site.

Targets associated with surface water contamination were identified in the HRS evaluation of this site. Rocky Creek is fished for human consumption within the zone of contamination. The Ocmulgee River is a source for outdoor recreation, comprising approximately 9 miles of the 15-mile target distance limit (TDL). Further, approximately 1.94 miles of wetland frontage has been identified as subject to Level II concentrations.


## 3. Summary of Comments

Comments were submitted by Drinker, Biddle & Reath LLP on behalf of Armstrong World Industries, Inc. (AWI) challenging the listing of Armstrong World Industries site (AWI site) on the National Priorities List (NPL).

AWI commented on its concern regarding the site name , asserting that the HRS evaluation of the AWI site includes sources not associated with AWI. As such, AWI sugg ested that the EPA rename the site after the “point of exposure,” rather than Armstrong World Industries.

AWI stated that particular products discussed in the HRS documentation record as containing polychlorinated biphenyls (PCBs) were not produced or recycled at AWI’ s Macon, Georgia facility, and are not a source of PCBs

1Armstrong World Industries NPL Listing Support Document September 2011

at the site. Further, AWI challenged the evaluation of source hazardous waste quantity for the sources at the site. AWI stated that contamination cannot be considered c ontiguous between sampling points at Sources 1 and 2 in the HRS evaluation, since contamination was not considered contiguous for Source 3.

AWI asserted that certain probable points of entry (PPEs) have been improperly excluded from the delineation of the hazardous substance migration pathway. AWI stated that other PPEs not discussed in the HRS documentation record are draining areas emanating from other off-sit e sources of contamination, such as from the Allied Industrial Park property 1 (AIP property) located adjacent to the AWI property. As such, AWI asserted that “premature conclusions” regarding attri bution at the site have been made, a nd that the ambiguity of origin of contamination at the site warrants further data co llection and evaluation befo re liability is assigned.


### 3.1 Support for listing

Comment: The State of Georgia submitted a letter (dated July 6, 2010) to the the EPA Region 4 Administrator stating that the State agrees that the Site poses a signifi cant threat to the public health and the environment and supports the EPA's efforts to propose the Site for inclusion on the NPL.

Response: The Armstrong World Industries site is being added to the NPL. Listing makes a site eligible for remedial actions under CERCLA, and the EPA will examine the Site to determine what response, if any, is appropriate. Actual funding may not necessarily be undert aken in the precise order of HRS scores, however, and upon more detailed investigation may not be necessary at a ll in some cases. The EPA will determine the need for Superfund monies for remedial activities on a site-by-site basis, taking into account the NPL ranking, State priorities, further site investigation, other response alte rnatives, and other factors as appropriate. The EPA will not stop work at some sites to begin work at other hi gher-scoring sites added to the NPL more recently.



### 3.2 Site Name

Comment : Armstrong World Industries (AWI) expressed concern regarding the site name. AWI asserted that two of the three identified sources - Source 2 (the Former Macon Naval Ordinance Landfill or FMNOL) and Source 3 (contaminated soil surrounding Source 2) include sources ot her than AWI, namely the owners and operators of the FMNOL, as well as other potential sources to Rocky Creek from the surrounding area. AWI asserted that “it would be more appropriate to name th e site after the point of exposure (the Rocky Creek Superfund Site) rather than after only one of a number of possible sources,” noting precedent for this approach. AWI requested that rename the site or at least include in the site na me a reference to the FMNOL and related facilities.

Response : The site name of Armstrong World Industries has b een retained. Names are preferred that accurately reflect the location or nature of the problems at a site and that are readily and easily associated with a site by the general public. As such, the name chosen reflects the long operational history of Armstrong World Industries at the Macon facility.

Regarding AWI’s comment that Sources 2 and 3 “include sources other than AWI,” disposal of waste in Source 2 has been documented as resulting from operations at the AWI facility. Since Source 3 is contaminated soil surrounding Source 2, the hazardous substances detected in Source 3 came to be located through migration resulting from the erosive processes at Source 2. As processe s at the AWI facility are known to have contributed hazardous substances to all site sources, the site name is appropriate.

1 The Allied Industrial Park property (AIP property), located east of the AWI Macon facility, is the location of the Former Macon Naval Ordnance Plant (FMNOP). Ordnance was manufactured at the FMNOP. The property is currently owned by the Macon-Bibb County Industrial Authority. Various commercial a nd/or industrial operations currently take place at the AIP property.

2Armstrong World Industries NPL Listing Support Document September 2011

The name of the site does not in any way restrict the evaluation of the site, its sources, its releases, or extent of contamination to only the practices of Armstrong World Industries. As the Federal Register in which the Armstrong World Industries site was proposed to the NPL (75 FR 64978, Section F) states, “the precise nature and extent of the site are typically not known at the ti me of listing.” Any and all areas of contamination will be explored during investigation activiti es outside of the listing process. The purpose of the NPL is to serve primarily as an informati onal tool for use in identifyi ng those sites that appear to present a significant risk to public health or the environment. The naming of the site does not reflect a judgment of the activities of the owner or operator of a site. It do es not require those persons to undertake any action, nor does it assign liability to any person.

This comment has no effect on the HRS site score or the decision to place the site on the NPL.


### 3.3 Liability

Comment : While liability concerns were not directly raised by AWI, it stated that “[c]onclusions about likely contributions . . . (whether AWI or other potential sour ces) should await further data collection and evaluation,” which could be interpreted as ra ising concerns about liability.

Response : Liability is not established by placing a site on the NPL. The NPL serves primarily informational purposes, identifying for the States and the public those facilities and sites or other releases which appear to warrant remedial actions. Inclusion of a facility or site on the NPL does not in itself reflect a judgment of the activities of an owner or operator, it does not require those persons to undertake any action, nor does it assign liability to any person. Subsequent government actions will be necessary to do so, and these actions will be attended by all appropriate procedural safeguards.

This comment has no effect on the HRS site score or the decision to place the site on the NPL.



### 3.4 Hazardous Substances A ssociated With Sources

Comment : AWI noted that the HRS documentation record states that three types of ceiling tiles were manufactured by AWI (Travertone Sanserra, Santaglio and Embossed Design) and that these tiles were coated with a formulation that contained Aroclor-1254, a commercial formulation of PCBs. AWI asserted that these products were manufactured for a “very short period of time” and were neither manufactured nor recycled at AWIs’ Macon facility. AWI requested that the EPA delete the reference to the ceiling tiles since they are not a source of PCBs at the site.

Response : The HRS documentation record has been revised at promulgation; the discussion regarding the handling or processing of the tiles in question has been removed. However, hazar dous substances, including PCBs, were appropriately associated with Sources 1, 2 and 3. That specific ceiling tile products were or were not manufactured or processed at the Macon facility does not impact the association of PCBs with site sources.

HRS Section 1.1, Definitions , defines source in part as, “Any area where a hazardous substance has been deposited, stored, disposed, or placed, plus those soils that have become contaminated from migration of a hazardous substance. . .”

One of the necessary criteria for establishing a site source, as directed by the HRS, involves associating hazardous substances with sources. HRS Section 2.2.2, Identify hazardous substances associated with a source , states in part:

Identify hazardous substances associated with a s ource. For each of the three migration pathways, consider those hazardous substances documented in a source (for example, by sampling, labels,

3Armstrong World Industries NPL Listing Support Document September 2011

manifests, oral or written statements) to be associated with that source when evaluating each pathway.

At this site, sources containing hazardous substances have been identified th rough sampling. The tables displayed in Section 2.2.2 of the HRS documentation record at proposal present (for Sources 1, 2 and 3) that hazardous substances, including PCBs, have been detected in th e site sources through sampli ng and analysis. Thus, these hazardous substances are associated with site sources (l andfills and contaminated soil) and not with a specific manufactured product at the facility.

Whether or not the specific products discussed by the commenter (Travertone Sanse rra, Santaglio and Embossed Design tiles) were manufactured or recycled at the facility does not discredit the findings that hazardous substances (including PCBs) were dete cted in site sources, nor the establishment of each source. Further, PCBs detected in releases downgradient from all site sources ar e appropriately attributable to the site, as PCBs were detected in all site sources that received waste from operations at the AWI facility (see section 3.7 of this support document for further discussion on attribution of PCBs to the site). Thus, the discussion of the manufacturing or handling of these specific products at the AWI Macon facility does not impact any scoring factor.

This comment has no effect on the HRS site score or on the decision to place the site on the NPL.


### 3.5 Source Hazardous Waste Quantity

Comment : AWI challenged the evaluation of source hazardous waste quantity for the scored sources. AWI stated that waste quantity was not calculated for Source 3 because “it is not known whether c ontamination in Source No. 3 is contiguous between sampling points”. AWI furt her questioned that since it is not known whether contamination is contiguous between sampling points for Sources 3 and a waste quantity was not calculated, why the same rationale was not used to calculate a source hazardous waste quantity value for Sources 1 and 2.

Response : The hazardous waste quantity evaluation for each of the site sources was appropriately scored in the HRS documentation record at proposal. First, a waste quantit y value of “greater than 0” was assigned to Source 3. Second, the waste quantities assigned to Sources 1 and 2 were based on the defined boundaries of the waste in these landfills using a waste quantity based on the area of th e sources. All site sources meet the HRS definition of a source. HRS Section 1.1, Definitions , defines “source” as:

Any area where a hazardous substance has been depos ited, stored, disposed, or placed, plus those soils that have become contaminated from migration of a hazardous substance. . . .

HRS Section 2.4.2.1, Source hazardous waste quantity , directs the scorer how to assign a hazardous waste quantity value to a source. It states:

For each of the three migration pathways, assign a source hazardous waste quantity value to each source (including the unallocated source) having a containment factor value greater than 0 for the pathway being evaluated . . .

For all pathways, evaluate source hazardous wast e quantity using the following four measures in the following hierarchy:

• Hazardous constituent quantity. • Hazardous wastestream quantity. • Volume. • Area.

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HRS Section 2.4.2.1.4 , Area , directs the evaluator to:

Evaluate the area measure using the area of the source (or area of the area of the observed contamination). Based on this area, designated as A, assign a value to the area measure as follows:

• For the migration pathways, assign the source a value for area using the appropriate Tier D equation of Table 2-5. [emphasis added]

HRS Section 2.4.2.1.5, Calculation of source hazardous waste quantity value , states:

Select the highest of the values assigned to the source (or area of observed contamination) for the hazardous constituent quantity, hazardous wastes tream quantity, volume, and area measures. Assign this value as the source hazardous waste qua ntity value. Do not round to the nearest integer.

As presented in Section 2.4.2.1, Source Hazardous Waste Quantity, of the HRS documentation record at proposal, the information available was not sufficient to evaluate the hazardous constituent qua ntity, hazardous wastestream quantity, or the volume measures for Sources 1, 2, or 3 (See pages 26, 39 and 50 of the HRS documentation record). As such, all site sources we re evaluated using the Area measure.

The following two subsections address how the source hazardous waste quantity was properly evaluated for Source 3 and Sources 1 and 2, respectively.

Source 3 Source 3, which was evaluated as source type “contaminated soil,” is composed of soil that became contaminated due to migration of a hazardous substance. That is, ac cording to the HRS definition of source as quoted above, “Any area where a hazardous substance has b een deposited, stored, disposed, or placed, plus those soils that have become contaminated from migration of a hazardous substance ,” [emphasis added] can be considered a

source.

As presented on page 50 of the HRS documentation record at proposal a value of “greater than 0” was calculated for this source hazardous waste quantity value. This value was assigned because the existence of hazardous substances within this source has been established th rough sampling and analysis (see Table 9 of the HRS documentation record at proposal).

Table 1 below identifies the samples taken from the cont aminated soil area. All show significant levels of contamination. Thus, the estimate of “greater than 0” is justified.

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Table 1: Hazardous Substances Associated with Source 3

Sample ID Hazardous Substance Hazardous Substance Concentration MRL Source Samples (0 to 6 inches bgs) PCB-1254 4,000 μg/kg 560 μg/kg Cadmium 2.3 mg/kg 0.86 mg/kg Lead 57 mg/kg 1.7 mg/kg AWI-216-SF

Manganese 750 mg/kg 2.6 mg/kg FML-300-SF Fluoranthene 240 μg/kg 200 μg/kg Benzo(a)anthracene 350 μg/kg 230 μg/kg Benzo(a)pyrene 560 μg/kg 230 μg/kg Benzo(k)fluoranthene 290 μg/kg 230 μg/kg Chrysene 560 μg/kg 230 μg/kg Fluoranthene 480 μg/kg 230 μg/kg Pyrene 470 μg/kg 230 μg/kg

PCB-1248 2,000J (2,000) μg/kg 440 μg/kg

PCB-1254 1,500 μg/kg 440 μg/kg PCB-1260 270 μg/kg 44 μg/kg Cadmium 4.5 mg/kg 0.71 mg/kg FML-301-SF

Lead 150 mg/kg 1.4 mg/kg
PCB-1248 1,200 μg/kg 110 μg/kg
Cadmium 6.2 mg/kg 1.7 mg/kg Lead 90 mg/kg 3.4 mg/kg FML-304-SF

Manganese 2,400 mg/kg 5.1 mg/kg PCB-1248 240 μg/kg 63 μg/kg Cadmium 1.6 mg/kg 0.95 mg/kg FML-305-SF
Manganese 3,600 mg/kg 2.9 mg/kg PCB-1248 470 μg/kg 110 μg/kg Cadmium 7.8 mg/kg 1.7 mg/kg Lead 90 mg/kg 3.4 mg/kg FML-308-SF

Manganese 1,800 mg/kg 5.1 mg/kg Cadmium 4.6 mg/kg 2.8 mg/kg FML-309-SF Lead 57 mg/kg 5.6 mg/kg Cadmium 6.5 mg/kg 3.2 mg/kg FML-309-SF- DUP Manganese 560 mg/kg 9.7 mg/kg
Source Samples (12 to 24 inches bgs) PCB-1254 1,600 μg/kg 530 μg/kg Cadmium 0.87 mg/kg 0.80 mg/kg Lead 82 mg/kg 1.6 mg/kg AWI-216-SB

Manganese 1,000 mg/kg 2.4 mg/kg

6Armstrong World Industries NPL Listing Support Document September 2011

7 Table 1: Hazardous Substances Associated with Source 3

Sample ID Hazardous Substance Hazardous Substance Concentration MRL Benzo(a)pyrene 310 μg/kg 190 μg/kg Chrysene 270 μg/kg 190 μg/kg

PCB-1248 4,500J (4,500) μg/kg 370 μg/kg

PCB-1260 170 μg/kg 37 μg/kg Cadmium 3.9 mg/kg 0.56 mg/kg FML-301-SB

Lead 100 mg/kg 1.1 mg/kg Benzo(a)pyrene 16,000 μg/kg 7,400 μg/kg PCB-1248 1,500 μg/kg 140 μg/kg Cadmium 77 mg/kg 2.6 mg/kg Chromium 61 mg/kg 5.1 mg/kg FML-304-SB

Lead 100 mg/kg 5.1 mg/kg PCB-1248 110 μg/kg 53 μg/kg Cadmium 5.2 mg/kg 0.80 mg/kg Lead 36 mg/kg 1.6 mg/kg FML-305-SB

Manganese 410 mg/kg 2.4 mg/kg Benzo(a)pyrene 7,100 μg/kg 6,500 μg/kg PCB-1248 7,400 μg/kg 1,300 μg/kg Cadmium 75 mg/kg 1.8 mg/kg Chromium 93 mg/kg 3.7 mg/kg FML-308-SB

Lead 170 mg/kg 3.7 mg/kg PCB-1248 9,600 μg/kg 1,700 μg/kg Cadmium 110 mg/kg 2.8 mg/kg Chromium 100 mg/kg 5.7 mg/kg FML-309-SB

Lead 140 mg/kg 5.7 mg/kg

However, because all samples taken from Source 3 contained hazardous substances and th e area is likely to have become contaminated by runoff or other migration from Source 2 (see discussion below regarding Source 2 contamination), it is reasonable to consider that the ar ea between the sample locations is contaminated and a source area could have been measured for Source 3 (see Table 1 above). As such, Figure 1 of this support document presents a calculated area measurement of Sour ce 3 which shows that Source 3 is approximately 94,400 square feet based on the area between locati ons of four samples taken from Source 3.

If this calculated area measurement we re used in the source hazardous waste quantity evaluation instead of the “greater than 0” area calculation used in the HRS doc umentation record, there would be no impact on the scoring of the surface water migration pathway hazardous waste quantit y scoring, nor on the site score. That is, if an area of 94,000 square feet were assigned to Source 3, then acco rding to Table 2-5 of the HRS, this value would be divided by 34,000, yielding an assigned value of 2.776. If this source hazardous waste quantity value were to be used in the HRS evaluation, the sum of the source h azardous waste quantity (for all sources) would increase from >174.06 to 176.836. According to Table 2-6 of the HRS, the value of 176.836 would still correspond with an assigned value of 100 to the pathway hazardous waste quan tity evaluation, the same as in the HRS documentation record at proposal.Armstrong World Industries NPL Listing Support DocumentSeptember 2011Figure 1: Source 3 Area Measurement8Armstrong World Industries NPL Listing Support Document September 2011

Sources 1 and 2 For Sources 1 and 2, the source type is landfill. A landfill is the location of an intended deposition of waste, the boundaries of which are known. When evaluating the area of this source, HRS Section 2.4.2.1.4 directs the scorer to evaluate the entire area of the source (in this case – landfill), not just the locations of the samples. Multiple samples from Sources 1 and 2 were documented to contain hazardous substances (see page 21 through 22 and 33 through 37 of the HRS documentation record at propo sal), thus the area measurement assigned to these sources reflects the consideration that the hazardous waste within these sources is continuous.

AWI’s assertion that contamination should not be inferred between sampling locations at Sources 1 and 2 because of the unknown extent of contamination between samples at Source 3 is inconsistent with the HRS, as discussed above. Even though a defined area was not assigned to Sour ce 3 in the evaluation of hazardous waste quantity in the HRS documentation record at proposal, as discus sed above, Source 3 was given a source hazardous waste quantity of “greater than 0” and therefore was assigned a value for waste quantity . As such, the way that the source hazardous waste quantity was calculated for Source 3 has no effect on the evaluation of hazardous waste quantity for Sources 1 and 2.

Further, given that the Source 3 sample locations came to be contaminated due to runoff from Source 2 toward the Source 3 sample locations, the area between the Source 3 sa mple locations is also in the overland flow path emanating from Source 2. Thus, it is reasonable to project contamination between the Source 3 sample locations.

This comment has no effect on the HRS site score or the decision to place the site on the NPL.


### 3.6 Probable Points of Entry from Sources

Comment : AWI asserted that the delineation of the hazardous substance migration pathway improperly excluded probable points of entry (PPEs) from the HRS evaluation. AWI pointed out that Figure 2 of the HRS documentation record shows PPE 1, but does not show PPE 2 or PPE 3.

Response : The PPEs from Sources 1, 2 and 3 were appr opriately described and presented in the HRS documentation record. AWI has confused PPEs included in the HRS evaluation with what was identified as PPEs in the 2009 Site Inspection Report (SI) (as shown on Figur e 3 of Reference 7 of the HRS documentation record). Not all PPEs identified in the SI report qualify as PPEs for the HRS evaluation.

PPEs 1 and 2, as scored in this evaluation, are presente d on Figure 2 of the HRS documentation record. PPE 1, which drains Source 1, is located south and downgradient from Source 1. PPE 2 drains Sources 2 and 3, and is evaluated as the interface between Source 2/Source 3 and surface water. Because Sources 2 and 3 are located adjacent to and/or within the surface water migration pa thway, PPE 2 has been estim ated as the interface betweenthese sources and surface water. PPE 2 is displayed on Figure 2 of the HRS documentation record as a yellowblack dashed line between surface water and the approximate boundaries of Source 2 and 3 as identified as PPE 2 in the Legend of Figure 2 of the HRS documentation record at proposal.

All PPEs were evaluated in accordance with the HRS. HRS Section 4.1.1.1 Definition of hazardous substance migration path for overland /flood migration component , states:

The hazardous substance migration path includ es both the overland segment and the in-water segment that hazardous substances would take as they migrate away from sources at the site:

• Begin the overland segment at a source and proceed downgradient to the probable point of entry to surface water.

9Armstrong World Industries NPL Listing Support Document September 2011

For Source 1, Section 4.1.1.1 of the HRS documentati on record discusses that overland flow from Source 1 “enters the drainage ditch that originates in the easter n portion of Source No. 1.” As shown on Figure 2 of the HRS documentation record, PPE 1 is located in the drainage ditch just southeast of Source 1.

From Sources 2 and 3, Section 4.1.1.1 of th e HRS documentation record explains that:

Overland flow from Source No. 2 (the commingled AWI remote landfill and the FMNOL) and Source No. 3 (contaminated soil surrounding the co mmingled landfill) travels south-southeast for about 0 to 375 feet into palustrine forested wetlands on the FMNOL property that are contiguous with Rocky Creek (Refs. 52; 60).

Because Sources 2 and 3 are in close proximity with su rface water (wetlands) in some locations, and in other locations within the wetlands, the interface where overland flow from Sources 2 and 3 meets surface water is approximated as the border between the sources and the wetland. This is shown on Figure 2 of the HRS documentation record at proposal as PPE 2.

Within the 2009 Site Inspection Report, the point where drainage ditches 3 and 4 enter Rocky Creek was labeled “PPE 2” and “PPE 3” respectively. These drainage ditches were not included in the HRS evaluation as probable points of entry associated with sources evaluated as part of the AWI site. These ditches may be conveying hazardous substances to Rocky Creek from other off-site sources from the Allied Industrial Park property (AIP property); however, the locations where these ditche s convey hazardous substances to Rocky Creek are downstream of PPEs 1 and 2 and several observed release sa mple locations and therefor e these ditches are not the cause of the significant increase in contamination attributed to the AWI site. As explained in section 3.7, Attribution, of this support document, the significan t increase of hazardous substances to the surface water migration pathway has been appropriately a ttributed in part to AWI site sources.

This comment has no effect on the HRS site score or the decision to place the site on the NPL.



### 3.7 Attribution

Comment : AWI commented that the Attribution section of the HRS documentation record “draws conclusions about sources prematurely,” and asserted that conclusions regarding contribution by sources (whether AWI or other potential sources) should await further data collection and evaluation. AWI stated that there are other potential contributors of contamination to Rocky Creek from the surrounding area.

Specifically, AWI stated that it believes that other PPEs are draining areas emanating from the Allied Industrial Park property, and that additional sampling is warranted at the Former Naval Ordinance Plant [formerly located at the AIP property]. AWI asserted that runoff and/or tri butaries from this Former Naval Ordinance Facility should be shown on the map, as they may be key points of entry for contaminants.

Response : At least part of the significant increase of hazardous substances in the observe d release samples for the surface water migration pathway has been appropriately attributed to AWI. Contam ination potentially entering Rocky Creek from the FMNOP is entering below the loca tion where observed releases from the AWI site have been documented.

Attribution was established at this site by first doc umenting that hazardous substances in the releases are associated with the site by showing that the contaminants are associated with site sources; second, by showing that hazardous substances were directly placed in surface water; and third, by documenting that there is no evidence suggesting that the significant increase in contaminant concentrations came from off-site sources. At this site, an observed release by chemical analysis has b een established and the significant increase of hazardous substances has been attributed to AWI. Additionally, there is evidence of direct deposition of hazardous substances into the surface water fro m sources associated with AWI.

10Armstrong World Industries NPL Listing Support Document September 2011

HRS Section 2.3, Likelihood of release , states in relevant part:

Establish an observed release either by direct ob servation of the release of a hazardous substance into the media being evaluated (for example, surf ace water) or by chemical analysis of samples appropriate to the pathway being evaluated (see s ections 3, 4, and 6). The minimum standard to establish an observed release by chemical analysis is analytical evidence of a hazardous substance in the media significantly above the background level. Further, some portion of the release must be attributable to the site . Use the criteria in table 2–3 as the standard for determining analytical significance. [emphasis added]

HRS Section 4.1.2.1.1, Observed release , directs the scorer to establish an observed release to surface water by demonstrating that the site has released a hazardous subs tance to surface water, based on either direct observation or chemical analysis. Regarding attrib ution, this section states in part,

Some portion of the significant increase must be a ttributable to the site to establish the observed release. . . .”

Pages 64 through 66 of the HRS documentati on record at proposal discussed attribu tion at this site. It stated in relevant part:

Elevated concentrations of PCBs were detected in samples collected from the AWI drainage ditch as well as along the entire length of the drainage easement, which begins just below where the drainage ditch ends at PPE 1 (Ref. 7, Appendix A, Figure 3, p. A-3; 7, Appendix B, Table 11, pp. B-24 through B-30; 7, Appendix D, p. D-5) (see Figures 2 and 3 of this HRS documentation record). None of the sediment samples collected from AIP’s western drainage ditch, upstream of its convergence with the AWI drainage easement (DD-502-SD, DD-503-SD, DD-504-SD, and DD-505-SD), contained PCBs (Ref. 7, Appendix A, Figure 3, p. A-3; Appendix E, pp. E-1255, E1257, E-1259, E-1261). Therefore, PCBs detected in the observed release are at least partially attributable to Source No. 1.

Source samples collected from Source No. 1 (WWTP landfill) during the EPA 2009 SI were analyzed only for PCBs. Sediment sample DD- 501-SD, collected from the AWI drainage ditch just as it leaves the property boundary of the AWI northern parcel and before it receives runoff from other possible sources upgradient of AWI, contained SVOCs and metals in addition to PCBs. These constituents were also detected in samples collected from Source No. 2 (the commingled AWI remote landfill and the FMNOL) (Refs. 7, Appendix A, Figure 3, p. A-3; 7, Appendix B, Tables 11 and 12, pp. B-24 through B-33; 7, Appendix E; 8, Appendix B, Tables 5 through 8, pp. B-8 through B-32).

Sediment samples collected from palustrine forest ed wetlands in the drainage easement contained SVOCs, PCBs, and metals, including benzo(a)anthracene (up to 7,100 μ g/kg), benzo(a)pyrene (up to 6,600 μ g/kg), benzo(k)fluoranthene (up to 6,100 μ g/kg), indeno(1,2,3-cd)pyrene (up to 5,700 J μ g/kg), phenanthrene (up to 4,600 μ g/kg), pyrene (up to 12,000 μ g/kg), PCB-1248 (up to 14,000 J- μ g/kg), PCB-1260 (up to 750 μ g/kg), cadmium (up to 12 mg/kg), chromium (up to 31 mg/kg), lead (up to 110 mg/kg), and manganese (up to 960 mg/kg) (Ref. 7, Appendix A, Figure 3, p. A-3; 7, Appendix B, Tables 11 and 12, pp. B-24 through B-33).

The same hazardous substances detected in sa mples from the AWI remote landfill (southern parcel of the AWI property) were also detect ed in the FMNOL, including benzo(a)anthracene, benzo(a)pyrene, benzo(k)fluoranthene, chrysen e, fluoranthene, pyrene, PCB-1254, cadmium, chromium, lead, and manganese (Refs. 7, Appendix E; 8, Appendix B, Tables 5 through 8, pp. B11Armstrong World Industries NPL Listing Support Document September 2011

8 through B-32) (see Table 4 of this HRS documen tation record). The area is prone to frequent flooding, potentially resulting in migration of hazardous substances from the commingled landfill to the surrounding area, because th e commingled landfill is located within the 100-year floodplain of Rocky Creek (Refs. 38; 39) and is severely eroded (Refs. 7, Appendix D, p. D-4; 9, p. 6; 19, p. 20).

. . . .
Source No. 3 sample locations FML301, FML305, FML308, FML309, and AWI216 are all located within HRS eligible wetlands (palustrine forested) (Refs. 7, Appendix A, Figure 3, p. A3; 52; 60). Samples collected from these locations contained elevated concentrations of benzo(a)anthracene, benzo(a)pyrene, benzo(k)fluor anthene, chrysene, fluor anthene, pyrene, PCB1248, PCB-1254, PCB-1260, cadmium, chromium, lead, and manganese (Refs. 7, Appendix E; 8, Appendix B, Tables 5 through 8, pp. B-8 through B-32) (see Table 9 of this HRS documentation record).

As cited above, hazardous substances detected in Sources 1, 2 and 3 have also been det ected in releases to surface water. The significant increase of hazardous substances found in the release can be attributed to the AWI site for the following reasons:

• As discussed in Section 3.1, Site Description, of this support document, evidence of hazardous substance deposition into Sources 1 and 2 has been established as the result of processes at the AWI facility. These hazardous substances have been de tected in release samples.

• Direct deposition of waste material containing h azardous substances in the observed release samples was documented within wetlands, which are part of the su rface water migration (see HRS Section 4.0.2 of the surface water pathway which identifies that in an HRS evaluation surface water includes wetlands adjacent to streams 2 ). This documents that hazardous substan ces in the observed release originated from the site.

• Background samples taken within Rocky Creek screen out the potential influence from off-site sources upgradient and west of the AWI facility. Detections of hazardous substances within the observed release samples were significantly greater than background levels in these upgradient samples (see Section 4.1.2.1.1 of the HRS documentation record at proposal).

• Hazardous substances from potential off-site sour ces associated with the AIP property may be contributing to the surface water migration pathway downstream of some release sample locations, through Drainage Ditches 3 and 4 (see Figure 3 of Reference 7 of the HRS documentation record). However, a significant increase of hazardous substan ces was established in release samples upgradient of the influence of these drainage ditches. That is, release samples DD-507-SD, DD-508-SD, DD-510-SD and RC-405-SD were documented to contain hazardous substances significantly greater than background levels – outside of the influence of Drainage Ditc hes 3 and 4 which drain the AIP property. The AIP property was identified on page 52 of the HRS doc umentation record as containing PCBs in three “isolated soil sample locations on the northern portion of the AIP property,” yet no PCBs were detected in any of the drainage ditches emanating from the AIP property.

2 HRS Section 4.0.2, Surface water categories , states:

... Rivers include:

• Perennially flowing waters from point of origin to the ocean or to coastal tidal waters, whichever comes first, and wetlands contiguous to these flowing waters.

12Armstrong World Industries NPL Listing Support Document September 2011

13 • Sediment samples (DD-502-SD, DD-503-SD, DD-504-SD and DD-505-SD) collected from the western ditch of the AIP property (see Drainage Ditch 2, as displayed on Figure 3 of Reference 7 of the HRS documentation record), did not contain PCBs. PCBs we re detected along the entire length of the drainage ditch downgradient of Source 1 and its associated PPE, which highlights the conveyance of hazardous substances to surface water from Source 1. Alt hough samples DD-502-SD, DD-503-SD, DD-504-SD and DD-505-SD were not specifically designated as relea se background samples, they serve to screen out the influence of hazardous substances emanating fro m the western portion of the AIP property.

For these reasons, the significant increase of hazardous s ubstances to the surface water migration pathway has been attributed to the site because site sources c ontaining hazardous substances resulting from AWI operations have been observed within the surface water migratio n pathway; observed release samples are documented as containing hazardous substances downstream of site sources and upstream of off-site sources (such as the AIP property); and, the significant increase of hazardous subs tances in observed release samples cannot be attributed to any off-site source.

This comment has no effect on the HRS site score or the decision to place the site on the NPL.



## 4. Conclusion

The original HRS score of this site was 50.00. Based on the above response to co mments, the score remains unchanged. The final scores for the Armstrong World Industries site are:

Ground Water Not Scored Surface Water 100.00 Soil Exposure Not Scored Air Not Scored HRS Site Score 50.00